Posts

Showing posts with the label ORA-01722

Featured Post

SQL Interview Success: Unlocking the Top 5 Frequently Asked Queries

Image
 Here are the five top commonly asked SQL queries in the interviews. These you can expect in Data Analyst, or, Data Engineer interviews. Top SQL Queries for Interviews 01. Joins The commonly asked question pertains to providing two tables, determining the number of rows that will return on various join types, and the resultant. Table1 -------- id ---- 1 1 2 3 Table2 -------- id ---- 1 3 1 NULL Output ------- Inner join --------------- 5 rows will return The result will be: =============== 1  1 1   1 1   1 1    1 3    3 02. Substring and Concat Here, we need to write an SQL query to make the upper case of the first letter and the small case of the remaining letter. Table1 ------ ename ===== raJu venKat kRIshna Solution: ========== SELECT CONCAT(UPPER(SUBSTRING(name, 1, 1)), LOWER(SUBSTRING(name, 2))) AS capitalized_name FROM Table1; 03. Case statement SQL Query ========= SELECT Code1, Code2,      CASE         WHEN Code1 = 'A' AND Code2 = 'AA' THEN "A" | "A

How to Resolve ORA-01722 Invalid Number Error in Oracle SQL Developer

Image
When working with Oracle SQL Developer, you may come across an error message that reads "ORA-01722: invalid number". This error can be frustrating and difficult to understand, especially if you're new to SQL. In this post, I will explain the cause of this error and provide a solution to resolve it. Cause of the Error - ORA-01722 Let's consider an example where we have two tables named "my_hr" and "my_dept". The "my_hr" table contains three columns - "name", "pay_id", and "user_id", while the "my_dept" table contains two columns - "name" and "user_id". CREATE TABLE my_hr ( name CHAR(20), pay_id NUMBER, user_id CHAR(6) ); CREATE TABLE my_dept ( name CHAR(20), user_id CHAR(6) ); Now, let's insert some sample data into these tables: INSERT INTO my_hr VALUES ('Srini', 567, '123456'); INSERT INTO my_dept VALUES ('Srini', '123456'); If we try to execu